Re: [PATCH 1/2] usb: configfs: allow UDC binding rule configured as binding to *any* UDC

From: Krzysztof Opasiak
Date: Wed May 04 2016 - 04:14:57 EST

On 05/03/2016 05:04 AM, changbin.du@xxxxxxxxx wrote:
> From: "Du, Changbin" <changbin.du@xxxxxxxxx>
> On most platforms, there is only one device controller available.
> In this case, we desn't care the UDC's name. So let's ignore the
> name by setting 'UDC' to 'any'.

Hmm libubsgx allows to do this for a very long time. You simply pass
NULL instead of pointer to usbg_udc.

It is also possible to do this from command line, just simply:

$ echo `ls -1 /sys/class/udc | head -n 1` > UDC

So if we can easily do this from user space what's the benefit of adding
this special "any" keyword to kernel?

> And also we can change UDC name
> at any time if it is not binded (no need set to "" first).

Not sure if:

$ echo "" > UDC

is really a problem. Personally I'm quite used to situation in which I
have to turn the light off before turning it on once again;)

Krzysztof Opasiak
Samsung R&D Institute Poland
Samsung Electronics